Download it and upload the WEN's IE CSS Support plugin to your site and Activate from dashboard then check your site. For border-radius, box-shadow, linear-gradient, Make sure all your "border-radius", "box-shadow" , and "linear-gradien" are in your theme's main stylesheet. Your main style usually named "style.css". Please email here for Quick support .
The plugin automatically scan your theme's main stylesheet and look for CSS3 properties to apply the markup.